DESCRIPTION: A number of biochemical features of the aids virus hamper efforts to control the disease or prevent the spread of infection. Included among them is the high degree of viral genetic variation, and therefore antigenic variation, within the envelope protein. A multifaceted study is proposed to correlate findings from a careful clinical and immunological analysis of HIV-1 in an infected male homosexual (MA/145) and an in-depth analysis of the diversity and functional consequences of this diversity in viral envelope genes. Virus isolates and cytotoxic T- lymphocytes (CTL) cell lines derived from cerebrospinal fluid (CSF) and PBL will be generated and PBMC, serum and semen samples will be obtained at frequent intervals. These will be combined with an extensive list of materials and information already available from this subject, including CTL lines, virus isolates, CSF and other tissue samples and -DNA sequence information, including samples which bracket the onset of AZT therapy. Complete envelope genes will be subjected to PCR amplification and cloning into a vaccinia virus expression vector. PCR products will be subjected to heteroduplex, restriction fragment length polymorphism and DNA sequence analyses over the 3' 700 bp of the gp120 coding sequence. Whole envelope proteins will be expressed in vaccinia virus and evaluated for CTL recognition and neutralization susceptibility, and inserted into a provirus backbone for analysis of virus cell tropism, syncytium inducing capacity, and cytopathogenicity. Extensive computer-aided analyses will be performed to track viral genotypes and identify genetic features which correlate with structural and functional differences. Detailed analysis of this and subsequent subjects provides a unique opportunity to study the natural history of infection and disease progression as well as provide valuable insight into the response to antiviral therapy and potentially vaccine design.